/*
Source : https://leetcode.com/problems/add-digits/
Author : nflush@outlook.com
Date   : 2016-07-15
*/

/*
258. Add Digits
 ?  

Question Editorial Solution  
 My Submissions 




?Total Accepted: 109422
?Total Submissions: 222419
?Difficulty: Easy



Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. 

For example: 

Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it. 

Follow up:
 Could you do it without any loop/recursion in O(1) runtime? 
*/
class Solution {
public:
    int addDigits(int num) {
        return (num%9) == 0 && (num != 0)? 9 : num%9;
    }
};
